Section Overview:
Autocatalytic formation of the fluorophore (also referred to as a chromophore) within the shielded environment of the polypeptide backbone during fluorescent protein maturation follows a surprisingly unified mechanism, especially considering the diverse natural origins of these useful biological probes. Shortly after synthesis, most fluorescent proteins slowly mature through a multi-step process that consists of folding, initial fluorophore ring cyclization, and subsequent modifications of the fluorophore. The spectral properties of fluorescent proteins are dependent upon the structure of the fluorophore as well as the localized interactions of amino acid residues in the immediate vicinity, and in some cases, residues far removed from the fluorophore. The interactive tutorials linked below explore fluorophore formation in a wide variety of spectrally diverse fluorescent proteins deduced from crystallographic studies.
Formation of the GFP Fluorophore
Explore the molecular re-arrangement that occurs during the formation of the enhanced green fluorescent protein (EGFP) fluorophore, which substitutes threonine for serine at position 65 in the amino acid sequence in this tutorial.
Formation of the DsRed Fluorophore
Observe the molecular re-arrangement that occurs during the formation of the DsRed fluorescent protein fluorophore, which has a similar imidazoline ring system, but substitutes glutamine for serine.
Formation of the ZsYellow (zFP538) Fluorophore
See the molecular re-arrangement that occurs during the formation of the ZsYellow fluorescent protein fluorophore featuring a novel three-ring system and peptide backbone cleavage due to the substitution of lysine for serine.
Photoconversion of the Kaede/Eos Green-Red Highlighter Fluorophore
Explore the molecular re-arrangement that occurs during the maturation of the Kaede fluorescent protein fluorophore, which emits green fluorescence, and the mechanism of photoconversion.
Formation of the eqFP611 Fluorophore
Explore the series of molecular re-arrangements that occur during the formation of the eqFP611 fluorescent protein fluorophore, which features a similar imidazoline ring system to EGFP, but substitutes methionine for serine as the first amino acid residue in the tripeptide sequence.
Formation of the HcRed Fluorophore
Observe the series of molecular re-arrangements that occur during the formation of the HcRed fluorescent protein fluorophore, which features a similar imidazoline ring system to EGFP, but substitutes glutamic acid for serine as the first amino acid residue in the tripeptide sequence.